44 BEACHYPODELLA. 



2. Shell pillar-shaped, white, finely striate ; axis cylin- 

 dric, biplicate or nodose-hooked. Jamaica. 



MYCHOSTOMA, sp. 44 to 48. 



III. Axis thin; either straight, weakly uniplicate, or spirally 

 gyrate. 



1. Last whorl carinate below, not free; shell sinistral, 



white, slender, densely striate, the whorls convex, 

 oblique; aperture oval, longer than wide; peris- 

 tome barely free or adnate above. Jamaica. 



APOMA, sp. 49, 50. 



2. Last whorl strongly carinate below, and with a lat- 



eral swelling or angle near the squarish or 

 rounded aperture; axis slender, straight, or 

 with one spiral; shell rather slender, small. 



a. Apical whorl very high. Jamaica. 



Geoscala, sp. 38 to 40. 



1). Apical whorl not greatly elevated. Haiti to 

 Trinidad; northern S. America to southern 

 Mexico. Brachypo delta, s. s., sp. 19 to 37. 



3. Last whorl angular below, shortly free; shell cor- 



neous, cylindric-tapering, truncate, densely 

 and finely striate; axis slender and straight. 



a. Apical whorls normal, costulate. Porto Rico 

 to eastern Cuba. Brevipedella, sp. 1 to 5. 



Z>. Apical whorls elevated. Jamaica. 



Simplicervix, sp. 41 to 43. 



4. Last whorl round below, at least near the aperture ; 



form slender. 



a. Neck round; apex usually entire, substriate; 



axis slender and straight. Eastern Cuba. 



Siphonol&mus, sp. no. 14. 



&. Neck moderate or long; axis cork-screw gyrate 

 in the later whorls; apex smooth; shell 

 slender, fusiform. Eastern Cuba, Santo 

 Domingo. Gyraxis, sp. 15 to 18. 



5. Last whorl angular or rounded below; shell obesely 



fusiform, striate; apex not attenuate, smooth; 

 whorls few, 12-13 in entire shells; axis slender, 

 straight. Haiti. Liparotes, sp. no. 12, 13. 



